Cut-out for electric lamps



(No Model.)

W. G` BREMER. GUT-OUT FOR ELECTRIC; LAMPS.

Patented Aug, 26, 1890 255m@ MMM TH: Noms vereis cm. Puo'rmnna, wAsmNmcN, u4 c.

UNITED STATES PATENT OFFICE.

WILLIAM GEORGE BREMER, OF ST. LOUIS, MISSOURI, ASSIGNOR TO THE UNITED ELECTRIC IMPROVEMENT COMPANY, OF GLOUCESTER CITY,

NEV JERSEY.

CUT-OUT FOR ELECTRIC LAMPS.

SPECIFICATION forming part of Letters Patent No. 435,029, dated August 26, 1890. Application filed April 24, 1890. Serial No. 349,208. (No model.)

.T0 all whom t may concern.-

Be it known that I, WILLIAM GEORGE BREMER, a subject of the Emperor of Germany, but residing at the city of St. Louis,in the State of Missouri, have invented certain new and useful Improvements in Cut-Outs for Electric Lamps, of which the following is a specication.

Heretofore electric lamps having two vertical supports have been provided with a spring-actuated short-circuiting lever pivotally connected with one of said supports and included in a shunt-circuithavingiu'terposed therein either a rigidly-supported tube capable of being melted or softened at a low temperature and provided with a conducting-cap or movable pinresting upon or against apellet or disk of similar material, so that when the intensity of the shunt-current was from any cause increased the rod or pellet softened or yielded and permitted the spring-actuated lever to short-circuit the generator or dynamo circuit. Although such types of cutouts were efficient in operation to a greater or less eX- tent, still their excessive cost, due largely to the number of parts and to the amount of machine-work incident to their construction, precluded their general employment.

. The principal objects of my present invention are, first, to dispense with both the movable pin and rigidly-supported tube provided with a cap or ferrule, and consequently to obviate the above mentioned disadvantages; second, to reduce the number and cost of the parts operating together to constitute the cuti out device; and, third, to provide a sensitive,

simple, and efficient cut-out.

My invention consists of a removable bar 0r rod of low electrical conductivity and capable of softening or melting at a low temperature interposed in a shunt-circuit and the said rod or bar melt-ed or softened when the intensity of the shunt-current is from any cause increased to permit a spring-actuated lever to cause said rod or bar to yield in the direction of its length and to short-circuit the dynamo or generator circuit.

My invention further consists in reducing the cross-section of said rod at a point without or beyond its support in order thatit may yield at that point Without fear of becoming jammed or wedged in the support thereof.

My invention further consists lin the construction of the switch-plug for removably supporting said rod or'bar and in its arrange` 55 ment with reference to a contact-spring for forming a hand-switch.

The nature and characteristic features of my invention will be more fully understood, taken in connection with the accompanying 6o drawings, forming part hereof, and in which`- Figure l is a view partly in elevation and partly in section of an electric-lamp holder or socket with my improved cut-out applied thereto and showing portions of an iucandescent electric lamp, shunt-circuit, the solid bar or rod removably supported and interposed in said circuit, and the means for" shortcircuiting the dynamo or generator circuit. Fig. 2 is a transverse sectional view on the 7o line c x of Fig. I, showing the switch-plug having a rod or bar with a reduced cross-section removably supported in arecess or chamber formed therein; and Fig. 311s asimilar View of the switch-plug, showing the extremity thereof iattened, filed, or otherwise cut away on one side or portion and rounded off on the opposite side or portion thereof.

Referring now to the drawings, R is a circular base-plate of insulating material, such 8o as hard rubber, having an aperture r formed therein. The vert-ical metal support A, secured to the base-plate R, is `bifurcated at d and is provided with a bearing d2 and a binding-screw or other terlninal device d3.. The vertical metal support A', secured to the baseplate R, is provided near its upper extremity with a binding-screw or\other terminal device at, and with a tapped or threaded aperture a5. The filament y is secured to the ver- 9o tical supports A and A in any preferred manner.

E is a bell-crank lever provided at one extremity thereof with a linger e and with a depending wing or arm Z for a purpose to be presently described. This bell-crank lever E is pivotally connected with the bifurcated support A. A spring F, interposed between the bell-crank lever E and the upper extremity of the support A, is in compression and Ioo tends to force the finger e of the lever E into close contact with the vertical support A;,

C is a metal plug having an external thread cut entirely around the surface thereof for engaging in the tapped orifice a5 of the support A and having one portion of the eX- tremity flattened, filed, or otherwise cut away laterally at the point c thereof in order that it may assume a somewhat eccentric form for the performance of Aa function to be hereinafter fully described.4 rlhe metal plug C is provided with a recess or chamber c for the reception of a solid bar or rod G of low electrical conductivity, but capable of melting,- softening, or fusing to a greater' or less degree at a low temperature. Onto the shank of the plug C is suitably mounted or secured an insulating thumb-piece D. The solid bar or rod G, of low electrical conductivity and capablevof melting, softening, or fusing at a comparatively moderate temperature, has a reduced cross-section at the point g in order to insure its yielding in the direction of its length at the point g. loosely mounted in the recess or chamber c of the metallic plug C in order that it may be readily and -quickly removed7 as may be required.

Heretofore in practice great difficulty was experienced in employing material or sub- .stances for the formation of the rods or bars G oWin g to the inability to secure the proper resistance, and various materials or compositions have been tried, but with little success until a composition composed of graphite and rubber was thoroughly tried, and then these materials, in order to be applicable for the purpose, had to undergo a particular treatment by mixing therewith a small percentage of sulphur and vulcanizing the mass, which rendered it hard, yet at the same time it was found afterassuming the required form for use that it would readily melt, soften, or even fuse under the influence of heat of an electric current brought into contact therewith sufficiently to enable these bars or rods to yield in the direction of their length. After experiments with various substances or materialsit was found that the bars or rods G, if made of rubber' and graphite in about equal proportion mixed with a small percentage of sulphurv and vulcanized in a suitable appliance in the manner above described, gave most excellent resultsthat is, the bars or rods G were capable of measuring a comparatively high resistance, at least one thousand ohms; but of course the resistance thereof Willvary with the change in the proportion through the aperture r in the base-plate R and through the thimble I. Y

I is the housing of the lamp socket or holder insulated from the thimble I.

I2 is a support for the bulb, globe, or shade (Illustrated in dotted lines in Fig. l.)

I4 is the glass bulb or vacuum-chamber of any preferred construction.

R2 is an insulating-disk supporting the vertical arms or conductors A and A and the housing I.

M and M are spring-actuated clamps of any preferred construction and serving to retain the glass bulb or vacuum-chamber in proper position.

N is a strip of spring metal secured to the 'vertical support A and adapted to contact with the extremital portion of the plug C, opposite to the part c, which is shown cut away in order that the filament y, by the bringing of said strip'N into contact therewith, may

be short-circuited or shunted, andthe lamp -within which is loosely mounted the rod or bar G, is secured or otherwise introduced through the tapped opening a5 in the vertical support A', with the extremity of the bar or rod G in contact with the depending wing or arml of the bell-crank lever E until the resistance of the spring F is overcome, whereupon the finger e is raised and the contact between this finger @and the vertical support A is broken. The lamp is then interposed in the dynamo or generator circuit in the usual orin any preferred manner, and the electric current entering the lamp is shunted and the main line' or generator current is caused to traverse the vertical supports A and A and the filament y, respectively. At the same time the current is shunted through the bell-crank leverE and wing or arm Z and the bar or rod G and support A. If the filament y becomes broken or otherwise injured, the intensity of the shunt-circuit will be greatly increased, and the bar or rod G will,

by reason of its low electrical conductivity,- be melted or softened sufficiently to yield in the direction of its length at the point g,

ICO

IIO

thereby causing the spring F to force the finger c into contact with the vertical support A', so that the electric current is shunted or short-circuited through the bell-crank lever E, and the lamp thereby cut out of the dynamo or 'generator circuit. When the broken or otherwise injured filament fy has been replaced by' a new one, the plug Gis withdrawn and the bar or rod G removed and replaced by a new one of similar construction. This change is readily effected, because the bar or rod will always yield at the point g, and therefore neverbecome jammed in the recess or chamber c of the plug C. The lamp is then readjusted in the manner hereinbefore j described for subsequent use. The dynamo or generator current may be short-circuited and the lamp extinguished without causing the bar or rod G to yield by rotating or unscrewing the plug C through a halfrevolution, whereupon' the spring F will force the finger e into contact with the vertical support A', While at the same time the portion opposite the cut-away portion c of the plug C will be brought by said half-turn of the switchplug C into contact with the strip ofspring metal N thereby closing the shuntcrcuit in a manner which can be readily understood, without further explanation from the drawings.

Having thus described the nature and objects of my invention, what I claim as new, and desire to secure by Letters Patent, is-

l. The combination, in an electric lamp, of two supports, a bell-crank lever pivotally attached to one of said supports, a spring interposed between said lever and support, a metal plug connected with the other of said supports and provided with an insulating thumb-piece, and a solid bar or rod of low electrical conductivity supported in said plug and yielding in the direction of its length at a low temperature, substantially as and for the purposes set forth.

2. The combination, in an electric lamp, of two supports, a bell-crank lever pivotally attached to one of said supports, a spring interposed between said lever and support, a metal plug provided with a threaded shank mounted in the other of said supports and provided with an insulating thumb-piece, and a solid bar or rod havinga reduced cross-section and of low electrical conductivity, substantally as and for the purposes set forth.

3. The combination, in a cut-out for electric lamps, of circuit-connections, a switchplug, a solid bar or rod composed of rubber and graphite capable of melting or softening at a low temperature mounted therein, and a spring-actuated bellcrank lever pressed against said bar or rod, substantially as and for the purposes set forth.

4. The combination, in a cut-out for electric lamps, of a circuit, a switch-plug, a removable bar or rod, melting, softening, or fusing at aV low temperature, mounted in said plug and having a reduced cross-section, and a pivotally-supported bell-crank lever pressed against said bar or rod and adapted to be included in said circuit, substantially as and for the purposes set forth.

5. The combination,in a cut-out device for electric lamps, of a circuit, a switclrplugprovided with a bar or rod of reduced crosssec tion, and a spring-actuated bell-crank lever pressed against saidbar or rod and adapted to be automatically included in said circuit, substantially as and for the purposes set fort-h.

G. The co1nbination,in a cut-out for electric lamps, of a sl1untcircuit, electrical connections, a switch-plug having a cutaway and rounded extreniital parts, and a bar or rod of reduced cross-section loosely mounted therein, and a spring-actuated bell-crank lever pressed against said bar or rod and included in said shunt-circuit, substantially as and for the purposes set forth.

7. The combination, in acut-out device for electric lamps, of a circuit and connections, a plug having eccentric and concentric portions, a bar or rod of low electrical conductivity mounted in said plug, a bell-crank le- Ver included in said circuit and pressed against said bar or rod, and a spring adapted to contact with the concentric portion of said plug, substantially as and for the purposes set forth.

8. The combination, in an electric-la`mp cutout, `of an insulating-housing I', two supports held therein, a bell-crank lever pivotally attached to one of said supports, a plug mounted in the other of said supports, and a solid bar or rod of low electrical conductivity loosely mounted therein and yielding in the direction of its length at a low' temperature, substantially as and for the purposes set forth.

9. The combination, in a cut-out for electric lamps, of two vertical supports, a switch-plug mounted in one of said supports and having eccentric and concentric extremital portions, a bar or rod of low electrical coductivity mounted therein, a spring attached to the other support and adapted to contact with the concentric extremital portion of said plug, a circuit, a bell-crank lever pivotally supported from one of said vertical supports, a spring interposed between said supportand lever, and said lever normally contacting with said bar or rod and adapted by the melting or softening of said bar or rod to contact with the other of said vert-ical supports, substantially as and for the purposes set forth.

10. A cut-out for electric lamps provided with two arms suitably supported within an insulating-housing, a switch-plug having an eccentric extremity, a removable bar or rod IOO IIO

mountedin said plug and yielding in the direction of its length, a pivotally-supported bell-crank lever, a spring adapted to contact with said plug, a filament, and circuit-connections, substantially as and for the purposes set forth.

11. The combination, in a cut-out for elecl tric lamps, of two supports, a switch-plug l mounted in one of said supports and having a solid bar or rod of low electrical conductivity and reduced cross-section mounted therein, and a flat spring secured to the other of said supports and adapted to contact with the enlarged extremital part of said plug, substantially as and for the purposes set forth.

In witness whereof I have hereunto set my signature in the presence of two subscribing witnesses.

XVM. GEO. BREMER.

Witnesses:

J. WALTER DoUcLAss, ARTHUR L. BosLEY. 

